Embodiments of the invention relate generally to a deep brain stimulation (DBS), and more particularly to a system and method for improving localization of an implanted DBS electrode via the use of a zero or ultra-short echo time (ZTE/UTE) magnetic resonance (MR) imaging technique.
Deep brain stimulation (DBS) is a well-established approach for treating disabling neurological symptoms and psychiatric disorders. The procedure uses a neurostimulator to deliver electrical stimulation to the brain by way of surgically implanted electrodes. Depending on the condition being treated, the electrodes can be used to target certain cells and chemicals within the brain or to target areas of the brain that control movement or regulate abnormal impulses. In this later case, the electrical stimulation can be used to disrupt abnormal nerve signals that cause tremor and other neurological symptoms. Over the past 20 years, more than 50,000 Parkinson's disease, essential tremor, dystonia and obsessive-compulsive disorder patients have seen significant symptom relief due to DBS treatment. Evidence now accumulates indicating that patients with chronic pain, post-traumatic stress disorder, and obesity may also benefit from DBS treatments.
In employing DBS treatments, locating the DBS electrode post-operatively is important for assessing surgery success in accurately implanting the electrode and for subsequently aiding device programming (i.e., selecting one or more electrodes from an array of electrodes for delivering electrical stimulation to the brain of a patient), with it being recognized that differences between an intended electrode target location and the actual electrode implantation location larger than 2 mm can result in a suboptimal outcome and may require reoperation. Post-operative locating of the DBS electrode is presently done via a performing of a post-implantation imaging technique—with computed tomography (CT) imaging or magnetic resonance (MR) imaging that utilizes a known long-readout technique (e.g., spoiled gradient recalled (SPGR) acquisition) being commonly employed to achieve the electrode localization. It is recognized, however, that presently used post-implantation imaging techniques for locating the DBS electrode can lead to imperfect electrode localization, whether it be due to beam hardening artifacts in a CT image acquisition or due to susceptibility induced signal loss in a long-readout MR image acquisition. For example, physical electrode diameters of 1.27 mm appear as ˜2.6 mm-wide signal blooms in CT images and ˜3.8 mm-wide signal voids in MR images acquired with long-readouts. Thus, it can be seen that a location of the DBS electrode may differ between acquired CT images and MR images, with differences in location on the CT and MRI images exceeding 1 mm being routinely found. An accurate localization of the DBS electrode may thus be difficult to achieve via use of standardly employed post-operative CT and long-readout MR image acquisition techniques.
It would therefore be desirable to have a system and method capable of accurately detecting the location of a DBS electrode post-operatively, with such locating being achieved via a fast scan-time as compared to standard, long-readout MR image acquisition. It would also be desirable for such a system and method to provide for the locating of individual electrode contacts of the DBS electrode, so as to enable selective activation of specific contacts of the electrode during DBS treatment.